Printed circuit boards comprise thin boards of insulating material (e.g., fiberglass impregnated with epoxy resin, paper impregnated with phenolic resin, plastic, polyimide film, silicon, and materials including copper or aluminum cores) that serve as the base for a printed circuit, i.e., a pattern of connections, or traces, superimposed (printed) onto a non-conductive substrate. The connections are metal strips (e.g., copper), and the pattern is typically produced using silk screen printing, photoengraving, PCB Milling, and/or electroplating. Electronic components are fixed to the board and connected to the printed circuit with solder. Component leads and integrated circuit pins may pass through holes (vias) in the board, or, alternatively, they may be surface mounted. Printed circuit boards may include components mounted on one or both sides, as well as internal signal layers, which allow more connections within the same board area. For example, most printed circuit boards are composed of conductive layers separated and supported by layers of insulating material (substrates) laminated (glued) together. Printed circuit boards, including those for high frequency circuits, may include one or more power and ground planes, e.g., large areas of copper for greater current carrying ability.
Printed circuit boards often include one or more components which require cooling. One technique for cooling such components is to control the airflow across the printed circuit board and its components (e.g., directing or pulling across cooler air towards heat generating components). However, printed circuit boards are usually designed for integration within a larger system, such as a Personal Computer (PC) tower, or the like. In such systems, the placement and orientation of the printed circuit board is often fixed in advance. This may be problematic. For instance, when a printed circuit board is vertically oriented, a heat generating component mounted at the bottom of the board may heat up devices directly above it. Moreover, the placement of other components external to the printed circuit board, including system fans for directing airflow over the board, are often fixed as well. Additionally, a heat generating component may be placed in close proximity to other components on a printed circuit board.
Existing techniques to control airflow across a printed circuit board include utilizing paper, plastic, or sheet metal walls which are preformed and then placed around components on the board. These walls direct, control, or prevent airflow across the printed circuit board as needed. However, utilizing such preformed walls increases the complexity of printed circuit boards. Further, walls formed separately from their corresponding printed circuit board must be matched up with each board and then affixed thereto, creating additional manufacturing steps.
Consequently, it would be desirable to provide a printed circuit board including a wall deposited directly on the board for controlling airflow across the board and its components.